This will allow you generate a filter list based on live registry data.
(You can also use a regular 'whois' client against filtergen.dan.me.uk to get the same output)

Options:	Enable Debug Mode Generate IPv6 Filter Generate cisco juniper force10 mikrotik prefix-list called       Permit up-to prefix size: / (CIDR size, e.g. 24 or 64)
Data Source:	RIPE RADB APNIC
AS-SET to Query:

Output from Filter List Generator:

%
% Filter List Generator
% Copyright(c) 2019, Daniel Austin MBCS
%
% usage:
%   [-D] [-6] [-RIPE | -RADB | -APNIC] [-f filtername -t filtertype [-upto N]] as-set
%
% -D for DEBUG mode (shows working calculations)
% -6 for IPv6 filter generation
% -RIPE for whois.ripe.net lookups
% -RADB for whois.radb.net lookups
% -APNIC for whois.apnic.net lookups
% -f will generate a cisco-style filterlist called 'filtername' (use -t filtertype as follows)
%      cisco (default)
%      juniper (basic support)
%      force10
%      mikrotik
% Additionally, if using -f/-t you may specify -upto N where N is the prefix size to permit up-to
%
% Using whois.radb.net for lookups
% Generating filter list for 'AS'
ERROR: no objects found